Systems and methods for processing waste materials

ABSTRACT

Systems and methods for processing waste material are presented. For some embodiments, the system comprises a chamber, an inlet, a fluid outlet, a metal outlet, and a magnet. The inlet is configured to selectively open and close. The inlet injects waste material into the chamber when the inlet is open. The waste material is suspended in a fluid medium, and comprises both ferromagnetic substances and non-ferromagnetic substances. The magnet is a selectively activated magnet coupled to the chamber. The magnet is configured to activate when the inlet is open, and deactivate when the inlet is closed. The magnet attracts the ferromagnetic substances from the waste material when the magnet is activated. The attracted ferromagnetic substances are released from the magnet when the magnet is deactivated. The metal outlet configured to selectively open and close. The metal outlet opens and expels the released ferromagnetic material from the magnet when the magnet is deactivated. The fluid outlet configured to selectively open and close. The fluid outlet opens when the magnet is activated, and expels any remaining waste material after the magnet has substantially attracted the ferromagnetic substances from the waste material.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional patentapplication Ser. No. 60/616,891, filed Oct. 7, 2004, which isincorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to waste processing, and moreparticularly to systems and methods for processing heterogeneous wastematerials.

BACKGROUND

Industry produces large amounts of waste that must be processed anddisposed of by waste operators. Most of this waste is heterogeneouswaste, which includes liquids and solids, which is friable andnon-friable, which melts at various temperatures, has varioussolidification temperatures, low auto-ignition temperatures, and highvapor pressure. The waste material also includes both ferrous andnon-ferrous metals in a wide range of sizes. This waste is oftencategorized by applicable environmental regulations as “hazardous waste”because of its often flammable, corrosive, or toxic character. Thus, thedisposal of such waste is heavily regulated by environmentalregulations.

There are inefficiencies associated with currently-available processesfor disposing of industrial waste. Thus, a heretofore unaddressed needexists in the industry for systems and methods of processing wastematerials.

SUMMARY

The present disclosure provides systems and methods of processing wastematerial.

Briefly described, in architecture, one embodiment of the systemcomprises a first chamber and a second chamber. The first chamberoperates at a first temperature, while the second chamber operates at asecond temperature. Preferably, the second chamber operates at a highertemperature than the first chamber.

The first chamber heats waste material to approximately the firsttemperature. The heating of the waste material produces vapors, whichare output through a vapor outlet of the first chamber. The remainingwaste material is conveyed to the second chamber.

The second chamber heats the remaining waste material to approximatelythe second temperature. The heating of the remaining waste materialproduces additional vapors, which are output through a vapor outlet ofthe second chamber. Any further remaining waste material is output fromthe second chamber.

In addition to providing systems for processing waste material, thepresent disclosure also provides methods for processing waste material.As such, one embodiment of the method is a multi-step process, whereinthe waste material is processed in two or more steps. Specifically, forsome embodiments, an earlier step of the process heats the wastematerial at a first temperature. This results in a release of vapors forthose materials having a boiling point that is lower than the firsttemperature. A subsequent step of the process heats some or all of theremaining waste material at a second temperature, which is preferablyhigher than the first temperature. The subsequent heating results in arelease of additional vapors for those materials having a boiling pointthat is lower than the second temperature. Such a multi-step process hasbenefits that cannot easily be obtained by other processes.

In yet another embodiment, among others, systems and methods areprovided for disposing of waste materials. For that embodiment, thesystem includes a vibrating screen that operates at above approximately750 vibrations per minute. The vibrations cause separation of particles,similar to a sifting mechanism. Some of the separated particles are thenremoved.

In still other embodiments, systems and methods for disposing of wastematerial are disclosed, in which a cross-belt magnet configuration isemployed to separate ferromagnetic substances from waste material. Forsuch embodiments, the system includes a first conveyor belt, a magnet,and a second conveyor belt. The first conveyor belt is configured tocarry waste materials in a first direction. The magnet is located inproximity to the first conveyor belt such that the first conveyor beltis within range of the attractive force of the magnet. The magnetattracts the ferromagnetic substances. The second conveyor belt isinterposed between the magnet and the first conveyor belt. The secondconveyor belt is positioned non-parallel to the first conveyor belt, andis configured to carry the attracted ferromagnetic substances in asecond direction, which is non-parallel to the first direction.

For other embodiments, systems and methods for processing waste materialare presented. For such embodiments, the system comprises a chamber, aninlet, a fluid outlet, a metal outlet, and a magnet. The inlet isconfigured to selectively open and close. The inlet injects wastematerial into the chamber when the inlet is open. The waste material issuspended in a fluid medium, and comprises both ferromagnetic substancesand non-ferromagnetic substances. The magnet is a selectively activatedmagnet coupled to the chamber. The magnet is configured to activate whenthe inlet is open, and deactivate when the inlet is closed. The magnetattracts the ferromagnetic substances from the waste material when themagnet is activated. The attracted ferromagnetic substances are releasedfrom the magnet when the magnet is deactivated. The metal outletconfigured to selectively open and close. The metal outlet opens andexpels the released ferromagnetic material from the magnet when themagnet is deactivated. The fluid outlet configured to selectively openand close. The fluid outlet opens when the magnet is activated, andexpels any remaining waste material after the magnet has substantiallyattracted the ferromagnetic substances from the waste material.

Other systems, devices, methods, features, and advantages will be orbecome apparent to one with skill in the art upon examination of thefollowing drawings and detailed description. It is intended that allsuch additional systems, methods, features, and advantages be includedwithin this description, be within the scope of the present disclosure,and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the disclosure can be better understood with referenceto the following drawings. The components in the drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the present disclosure. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is a block diagram showing one embodiment, among others, of aheterogeneous waste processing system.

FIG. 2 is a block diagram showing, in greater detail, one embodiment ofthe liquid handling system of FIG. 1.

FIG. 3 is a block diagram showing one embodiment, among others, of ametal separation system associated with a heterogeneous waste processingsystem.

FIG. 4 is a block diagram showing one embodiment, among others, of apipeline magnet system associated with a heterogeneous waste processingsystem.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference is now made in detail to the description of the embodiments asillustrated in the drawings. While several embodiments are described inconnection with these drawings, there is no intent to limit thedisclosure to the embodiment or embodiments disclosed herein. On thecontrary, the intent is to cover all alternatives, modifications, andequivalents.

As noted above, industry produces large amounts of waste that must beprocessed and disposed of by waste operators. However, there areinefficiencies associated with currently-available processes fordisposing of industrial waste. The present disclosure provides systemsand methods of processing waste material.

Briefly described, for some embodiments, a multi-step process isprovided in which waste material is processed in two or more steps.Specifically, for some embodiments, an earlier step of the process heatsthe waste material at a first temperature. This results in a release ofvapors for materials having a boiling point that is lower than the firsttemperature. A subsequent step of the process heats some or all of theremaining waste material at a second temperature, which is preferablyhigher than the first temperature. The subsequent heating results in arelease of additional vapors for those materials having a boiling pointthat is lower than the second temperature. Such a multi-step processpermits efficient handling of waste materials.

FIG. 1 is a block diagram showing one embodiment, among others, of awaste processing system. In the embodiment of FIG. 1, the systemcomprises a feed hopper 20, which is configured to receive heterogeneouswaste material, also referred to as feedstock F. For some embodiments,the feed hopper 20 is mounted on load cells 22, thereby permittingweight-based, rather than volumetric, feed control. For someembodiments, the feed rate can be designed for approximately 12000 lbsper hour. Since such volumetric control of inputs is known in the art,further discussions of the feed hopper 20 and the load cells 22 areomitted.

The feed hopper 22 provides the waste material 21 to a first chamber 40through an airlock 30. The airlock 30, for some embodiments, is a knifegate, which largely isolates the first chamber 40 from the feed hopper20. The airlock 30 limits air infusion into the first chamber 40, whichis, for some embodiments, a sub-ambient pressure chamber 40. Thisisolation removes dependence on a dynamic seal. Also, the improved sealslimit or prevent appreciable influx of air into the system, therebyreducing the chances for unplanned oxidation and also reducing theamount of non-condensable gases that flow through the system. Thereduced flow also reduces the amount of condensable vapors that flow outof the system since the mole fraction (vapor pressure) is constant.

For some embodiments, an inerting gas 31 (e.g., carbon dioxide,nitrogen, etc.) is injected into the airlock 30 to displace air or otheroxidizing agents. This reduces the oxidation that can occur in thesubsequent stages of the waste processing system.

Since such isolation mechanisms and inerting gases are known in the art,further discussion of the airlock 30 is omitted. However, one havingskill in the art will appreciate that other mechanisms for isolating thefirst chamber 40 from the feed hopper 20 can readily be employed.

The first chamber 40, for some embodiments, is a volatiles evaporator.As such, for those embodiments, the first chamber 40 comprises a heatedscrew 48 having hollow threads 46. The heated screw 48 is operativelycoupled to a heater 44, which is configured to provide heat to theheated screw 48. Preferably, the heated screw 48 is heated using a heattransfer fluid 43, such as, for example, oil. For some embodiments, theheated screw 48 is approximately three feet in diameter andapproximately thirty feet in length. In operation, the heater 44circulates the heat transfer fluid 43 to the heated screw 48, therebymaintaining the temperature of the heated screw 48 at a relativelyconstant temperature. The heating of the screw 48 results in acorresponding heating of the interior of the first chamber 40. For someembodiments, the temperature of the heat transfer fluid 43 ranges fromapproximately 650 to approximately 700 degrees Fahrenheit, therebyheating the first chamber 40 to approximately 600 degrees.

Given this configuration, when the waste material 21 enters the firstchamber 40, the hollow threads 46 of the screw 48 move the wastematerial 21 through the first chamber 40 while progressively heating thewaste material 21. The heating of the waste material 21 results in therelease of vapors 41. For example, if the screw 48 is maintained atapproximately 650 degrees, then waste material having a boiling pointthat is lower than approximately 650 degrees will vaporize due to theapplied heat. For ease of reference, these vapors 41 are referred toherein as lower-boiling point vapors 41. The heated surface also limitscondensing of vapors, thereby avoiding buildup of material. For someembodiments, the first chamber 40 can be jacketed, thereby minimizingcold spots where vapors could otherwise condense.

The lower-boiling point vapors 41 are evacuated from the first chamber40 by a first scrubbing system 50. For some embodiment, the firstscrubbing system 50 comprises one or more Venturi scrubbers, which areknown in the art. One embodiment of the first scrubbing system 50 isdescribed in greater detail with reference to FIG. 2. These Venturiscrubbers are particle removers, which remove fine particles fromvolatile, hazardous, or corrosive gas streams. Since Venturi scrubbersare widely used throughout the chemical industry, further discussion ofVenturi scrubbers is omitted here.

The first scrubbing system 50 is operatively coupled to a heat exchanger130, which is, in turn, operatively coupled to a cooling tower 140. Thefluid 131 circulating in a particular Venturi scrubber may also serve asthe condensate for that Venturi scrubber. A cooling tower 140 and a heatexchanger 130 can be located on each loop to provide the appropriatecooling mechanism for the Venturi scrubber.

Upon receiving the lower-boiling point vapors 41, the first scrubbingsystem 50 cools the received vapors 41. The cooling of the vapors 41produces one or more condensates 53 and various non-condensable vapors51, such as, for example, carbon dioxide, air, etc. Both the condensates53 and the non-condensable vapors 51 are output from the first scrubbingsystem 50.

The non-condensable vapors 51 are input to a second-stage scrubbingsystem 90, which, for some embodiments, may be Venturi scrubbers similarto those in the first scrubbing system 50. The resulting output of thesecond-stage scrubbing system 90 are additional condensables 93 andresidual non-condensable vapors 91.

The purge from each Venturi scrubber, for some embodiments, would be bylevel control. Sufficient cooling water at or below approximately 86degrees Fahrenheit can be circulated through the heat exchangers 130 tocool most of the condensable vapors. The non-condensables that passthrough a primary Venturi scrubber to a secondary Venturi scrubber arecooled to below 90 degrees using chilled water. The non-condensablevapors 91 comprise these cooled gases.

The residual non-condensable vapors 91 are directed to a thermaloxidizer unit 160 through an exhauster 150. As is known in the art, thethermal oxidizer unit 160 destroys air toxics and volatile organiccompounds that are discharged. For some embodiments, the additionalcondensables 93 (e.g., water, lower boiling point hydrocarbons, etc.)are directed to a liquid handling system 170 for further processing.

The liquid handling system 170 receives various condensates, processesthose condensates, and outputs oil product 173, waste fuel 175, wastewater 177, and clean waste water 179. Since the liquid handling system170 is discussed in detail with reference to FIG. 2, no furtherdiscussion of the liquid handling system 170 is provided with referenceto FIG. 1.

Referring back to the first chamber 40, the heating of the wastematerial 21 also results in remaining waste material 45 (e.g., meltedplastics, solids, and other molten material) that remains after thelower-boiling point vapors 41 have been released. The remaining wastematerial 45 is discharged to a second chamber 60, which further heatsthe remaining waste material.

The second chamber 60 comprises an electrically-heated screw 62, whichis configured to heat the interior of the second chamber 60, preferablyto a temperature that is higher than the temperature of the firstchamber 40. For some embodiments, that temperature is approximately 1000degrees Fahrenheit. At this temperature, some of the residual plasticsand fibrous materials may crack. Also, at this temperature, char becomesfriable. In some embodiments, the second chamber 60 is capable ofapproximately 6000 lbs per hour of input. For some embodiments, theelectrically-heated screw 62 may be approximately three feet indiameter, and approximately twenty feet in length.

When the remaining waste material 45 enters the second chamber 60, theelectrically-heated screw 62 moves the remaining waste material 45through the second chamber 60 while heating the remaining waste material45. Since, for this embodiment, the temperature of the second chamber 60is higher than the temperature of the first chamber 40, the heating ofthe remaining waste material 21 results in the release of vapors 61 thathave a higher boiling point than those from the first chamber 40. Forexample, if the electrically-heated screw 62 heats the second chamber toapproximately 1000 degrees, then material having a boiling point that islower than approximately 1000 degrees will vaporize due to the appliedheat. For ease of reference, these vapors 61 are referred to herein ashigher-boiling point vapors 61. Examples of higher-boiling point vapors61 may include various plastics and hydrocarbons.

These higher-boiling point vapors 61, which are output from the secondchamber 60, are provided to a second scrubbing system 70. For someembodiments, the second scrubbing system 70 comprises one or moreVenturi scrubbers, similar to those described with reference to thefirst scrubbing system 50. Upon receiving the higher-boiling pointvapors 61, the second scrubbing system 70 cools those vapors 61,resulting in the production of various condensates 73 and variousnon-condensable vapors 71.

The non-condensable vapors 71 are conveyed to the second-stage scrubbingsystem 90, where those non-condensable vapors 71 are disposed in amanner similar to the vapors 51 from the first scrubbing system 50. Thecondensates 73 are provided to the liquid handling system 170 forfurther processing.

Returning to the second chamber 60, once the higher-boiling point vapors61 have been released, any residual waste 65 (e.g., metal, char, otherremaining waste material) is output from the second chamber 60 to acooling chamber 80. It should be appreciated that the residual waste 65can also be further separated, if desired. For example, the secondchamber 60 can optionally include a port 64 for expelling any moltenplastic 67 for recycling. Thus, for those embodiments, the dischargedresidual waste 65 may have a lower concentration of molten plastics.

The cooling chamber 80 comprises one or more water sprays 92, which areconfigured to spray and cool the material in the cooling chamber 80. Assuch, the cooling chamber receives a water supply 95 from a quenchingsystem 94, which is operatively coupled to the cooling chamber 80. Thewater supply 95 that is provided by the quenching system 94 may be freshwater 97, or a portion of the waste water 177 from the liquid handlingsystem 170, or a combination of both 97, 177.

The cooling chamber 80 receives the residual waste 65, namely, furtherremaining waste material. Since the residual waste 65 has been exposedto extreme temperatures, some of the waste 65 is activated. In otherwords, some of the residual waste 65, such as any activated char, canreact with air and self ignite, thereby posing a hazard. The coolingchamber 80 quenches the residual waste 65 to deactivate the residualwaste 65. For some embodiments, the residual waste 65 is cooled toapproximately 230 degrees Fahrenheit. The hydrating of the char alsosteam strips the remaining high-boiling hydrocarbons. Also, metalswithin the residual waste 65 can be cleaned and cooled by the sprays 92.

In the process of spraying the residual waste 65, scrubbed vapors 81(e.g., water vapors and scrubbed hydrocarbons) are released. Thereleased vapors 81 are provided to a third scrubbing system 110, whichfunctions similar to the first scrubbing system 50 and the secondscrubbing system 70. The resulting condensates 113 and non-condensablevapors 111 from the third scrubbing system 110 are provided to theliquid handling system 170 and the second-stage scrubbing system 90,respectively, for further processing.

The deactivated residual waste 85 (e.g., metals, hydrated char, etc.)from the cooling chamber 80 is conveyed to a metal separation system 200via an airlock 100. The metal separation system is discussed in detailwith reference to FIG. 2. Again, the airlock 100 isolates the coolingchamber, which may be a sub-ambient pressure chamber, from the metalseparation system 200.

As seen with reference to FIG. 1, by providing multiple steps forprocessing waste, much of the waste that is not processed in an earlierstep can be processed in subsequent steps, thereby providing greaterhandling of waste material. Additionally, progressively heating tohigher temperatures avoids cracking of low molecular weighthydrocarbons.

FIG. 2 is a block diagram showing, in greater detail, one embodiment ofthe liquid handling system 170 of FIG. 1. As shown in FIG. 2, and asdiscussed with reference to FIG. 1, the liquid handling system 170receives its input from the following: the first scrubbing system 50,the second scrubbing system 70, the third scrubbing system 110, and thesecond-stage scrubbing system 90. For convenience, the scrubbing systems50, 70, 90, 110 are collectively referred to as an integrated gashandling system 120. The integrated gas handling system 120 utilizesparallel flow, which removes the vapors as they are formed and reducesthe velocities within a specific chamber, thereby reducing the entrainedsolids. For some embodiments, much of the vapor streams will be reducedto a temperature of approximately 120 degrees Fahrenheit in the firstcontact with a scrubbing system. This lower first stage temperaturereduces high temperature liquid streams and improves condensationinefficiencies.

In the embodiment of FIG. 2, the first scrubbing system 50 comprisesthree Venturi scrubbers V1, V2, and V3. These Venturi scrubbers V1, V2,V3 are placed such that the saturated vapors super heat is minimal andthat they do not condense and reflux prior to exiting the evaporator.The vapors are withdrawn at these three places, thereby making separatecuts possible, which maximize the possibility of producing a sealableproduct. Each Venturi scrubber V1, V2, V3 is sized to be able to takethe full vapor flow from any probable feed composition at anapproximately 12000 lbs per hour feed rate. For some embodiments, theVenturi scrubbers V1, V2, V3 are positioned in parallel so that anysingle scrubber may be taken off line for service during times ofslightly reduced flows. This permits maintenance without complete shutdown of the system.

Having multiple Venturi scrubbers allows the process to separatelyevacuate the vapors that have been somewhat separated according to theirrespective boiling points. At times, non-chlorinated fractions can beseparated and potentially sold as recycled hydrocarbons having asignificant value. This is especially so if they are redistilled tospecification.

For some embodiments, the Venturi scrubbers can be controlled to hold aset inlet temperature. If the temperature of at the inlet of V1 risesabove its set point, then it is drawing vapor from the next highertemperature zone. The flow rate would be decreased if V2 could not beincreased. Likewise, if V2 inlet temperature falls below a set point,then V1 would be increased, if possible, else V2 would be reduced. Forsuch embodiments, the vapor inlet temperature can be configured tocontrol the distribution of flow among the various Venturi scrubbers.

The liquid handling system 170 comprises three oil-water separators 202,206, 208. The first oil-water separator 202 and the third oil-waterseparator 206 receive their inputs from various scrubbers of theintegrated gas handling system 120. For the embodiment of FIG. 2, thefirst oil-water separator 202 receives condensate 53 a, 53 b from V1 andV2, respectively. Optionally, the first oil-water separator 202 can alsoreceive the condensate 93 from the second-stage scrubbing system 90.

Upon receiving condensates 53 a, 53 b, the first oil-water separator 202separates the condensate 53 a, 53 b into waste fuel 175, waste water177, and wet char 299, which are output from the liquid handling system170. The waste fuel 175 is a higher-BTU (British Thermal Unit) wasteoutput that has a lower disposal cost, while the waste water 177 is alower-BTU waste output that has a relatively higher disposal cost. Thewet char 299 includes various suspended solids.

For some embodiments, a portion of the waste water 177 is directedthrough a fine separation unit 210, which, to a certain extent, breaksdown emulsions and provides fine filtration. For such embodiments, thefine separation unit produces clean waste water 179 as the output to theliquid handling system 170.

The third oil-water separator 206 receives, as its input, condensates 53c, 73, 113 from V3, the second scrubbing system 70, and the thirdscrubbing system 110, respectively. The third oil-water separator 206separates the condensates 53 c, 73, 113 into wet char 299, which isoutput from the liquid handling system 170, and various oils andsuspended solids 207. The oil and suspended solids 207 are conveyed to afiltration back wash unit 208, which filters the suspensions from theoil. The suspensions are output as wet char 299. The oil is output tothe second oil-water separator 204 having a fine coalescer.

The second oil-water separator 204 further breaks down emulsions andproduces, as its output, oil product 173 and a relatively small amountof waste water 177, which are both output from the liquid handlingsystem 170. As discussed with reference to FIG. 1, a portion of thewaste water 177 may optionally be directed to the quenching system 94 toprovide part of the water supply 95 for use in the cooling chamber 80.

The liquid handling system 170 of FIG. 2 separates the solids from theliquids and the water from the oil. Given the configuration of FIG. 2,the separation of high water streams from low water streams reduces theinclusion of water in the oil streams and increases the likelihood ofproducing a recyclable oil product 173. Also, the waste fuel 175 has ahigher heating value (higher BTU) than current systems, and the cleanedwaste water 179 can be disposed at reduced prices. The oil product 173results from better separation of the lower boiling hydrocarbons andhydrochloric acid from the higher boiling and relatively chlorine-freematerials. The reduced water in the product stream aids in dissolvingmuch of the dissolvable matter in the product oil. Much of thecondensing and entrained solids are removed in the automaticallybackwashed screens prior to the heat exchanger 130, since thetemperature of the circulating liquids should, preferably, not exceedapproximately 110 degrees. Hence, the fouling of the Venturi scrubbersshould be reduced.

FIG. 3 is a block diagram showing one embodiment, among others, of ametal separation system 200 associated with a waste processing system.The metal separation system 200 converts metal bearing waste intomultiple streams, which can be recycled if a market exists. The metalseparation system 200 handles non-volatile fractions, including char,metal, and nonmagnetic inert substances such as, for example, glass,gravel, soil, sand, etc. As shown in FIG. 3, the metal separation system200 comprises a conveyor 240, a high-frequency vibrating screener 250, amagnet 260, a chute 270, and another scrubber 220.

Continuing from the description of FIG. 1, the deactivated residualwaste 85 (e.g., metals, hydrated char, etc.) from the cooling chamber 80(FIG. 1) is conveyed to the metal separation system 200 via the airlock100 (FIG. 1). The conveyor 240, which is preferably enclosed to bedust-tight, receives the residual waste 85. The conveyor 240 isoperatively coupled to the scrubber 220, which draws the lighter gasesand dust 241 from the conveyor 240. The scrubber 220, which ispreferably a Venturi scrubber, again separates waste water 177 andnon-condensables 221 for disposal, as described with reference to FIG.1.

The conveyor 240 discharges the remaining particles 245 onto aninclined, high-frequency vibrating screener 250 that is also enclosed tobe dust-tight. For some embodiments, the incline is at approximately 32degrees from horizontal. Preferably, the vibrating screener 250 operatesabove approximately 750 vibrations per minute. More specifically, thescreener 250 operates somewhere between approximately 900 andapproximately 1800 vibrations per minute.

The frequency is set to a level that is sufficient to overcome thestatic forces that bind the carbon and the soil in the remainingparticles 245. This is relatively difficult, since the surfaces of themetal are typically dented, folded, or wrinkled.

As a result of the vibration, the fine particles 251 are shaken freefrom the larger particles, and fall through the screen 250. Theremaining larger particles 255 roll off of the inclined screen 250.These fine particles 251, which result from the vibration of thescreener 250, are removed to a recirculation loop 340, which isdescribed in greater detail with reference to FIG. 4.

Once the fine particles 251 are removed, the larger particles 255 aresubjected to a magnetic separation process. For some embodiments, themagnet 260, which is preferably an overhead cross-belt electromagnet, isused to accelerate the metal components 265 upward against the belt thattravels to the edge of the magnet 260.

Specifically, for some embodiments, the cross-belt arrangement isconfigured such that a lower first conveyor belt moves materials in apredefined direction. Above the first conveyor belt resides a secondconveyor belt, which moves in a direction that is substantiallyperpendicular to the direction of the first conveyor belt. That secondconveyor belt surrounds a magnet.

Thus, the larger particles 255 are moved along the first conveyor beltuntil they are brought into the range of the magnet. As those particles255 come into range, the metal components 265 are attracted by themagnet and accelerated upward. Since the second conveyor belt surroundsthe magnet, the metal components 265 are carried off in by the secondconveyor belt in a direction that is substantially perpendicular to thefirst conveyor belt. The non-metal components 261 stay on the firstconveyor belt, since they are not attracted by the magnet.

The field of the magnet diminishes toward the edge, thereby causing themetal 271 to fall free into the chute 270. This metal 271 can then berecycled or disposed. The non-magnetic substances 261 are not attractedby the magnet 260, and are disposed accordingly.

Since the metal can be relatively large (e.g., whole cans, etc.), theclearance between the lower conveyor belt and the cross belt should besufficiently large to accommodate the various sizes of metals. For someembodiments, this can be somewhere between approximately 7 inches toapproximately 12 inches.

For some embodiments, an electromagnet is preferable to a static magnetbecause of the manipulability of the magnetic field. For example, thinpieces of metal are not easily attracted due to their reduced surfacearea. However, once attracted, these thin pieces typically acceleratequickly, thereby impacting the belt with sufficient force to degrade thebelt in a relatively short time span. The greater acceleration of apermanent magnet would be detrimental to the belt, yet not be sufficientto attract thin metal fragments.

Once attracted, the impact of the metal against the belt causes morenon-magnetic particles to shake free from the ferrous metals.

FIG. 4 is a block diagram showing one embodiment, among others, of apipeline magnet system 300 associated with a waste processing system. Asshown in FIG. 4, the pipeline magnet system 300 includes a recirculationloop 340. Specifically, for the embodiment of FIG. 4, the recirculationloop 340 comprises a pump 330, a pipeline grinder 350, a pipeline magnet360, and a flow meter 370.

In operation, the fine particles or fines 251 enter from thehigh-frequency vibrating screener 250 (FIG. 3) into a hydropulper 320,which includes a grinding chamber 310. In addition to the fines 251, thehydropulper 320 receives, as its input, either waste water 177, wastefuel 175, or a combination of waste water 177 and waste fuel 175 fromthe liquid handling system 170. The liquid 175/177 and fines 251 areground together to form a sludge-like mixture 315, which is output fromthe hydropulper 320 to the recirculation loop 340.

The sludge-like mixture 315 from the hydropulper 320 is fed through thepump 330, which drives the recirculation loop 340. Preferably, themixture 315 leaves the hydropulper 320 through half-inch holes, and intothe recirculation loop 340. The pump 330 is controlled by the flow meter370, which maintains the flow at a predetermined rate. The sludge-likemixture 315 is fed to the pipeline grinder 350, which further grinds thesludge-like mixture 315, resulting in finer suspended particles withinthe mixture 355. The resulting fine mixture 355 is directed to apipeline magnet 360, which attracts ferromagnetic material 361 using themagnetic field of the magnetic 362. A portion of non-ferrous material(and remaining ferrous material) 365 is output, while the remainingportion of the non-ferrous material 365 is fed back to the hydropulper320 for recirculation.

Given this configuration, this embodiment of the pipeline magnet system300 functions as a trap for magnetic material. Also, the configurationof FIG. 4 permits controlled discharges, preferably in timed intervals,of a small amount of liquid within the metal into a container.

For some embodiments, each time the process shuts down, and eachpredetermined interval (e.g., twenty minutes), the pump shuts down forseveral seconds to purge the metal. In one embodiment, among others, thepurge occurs as follows. The intake and discharge valves close, theelectromagnet de-energizes, and a drain valve on the bottom of thechamber opens to discharge the metal and some liquid by gravity. Tocomplete the cycle, the purge valve closes, the intake and dischargevalves open, the magnet re-energizes, and the system restarts if thecycle was not complete. Preferably, the liquid can be decanted in orderto dispose of the metal fines.

Having the pipeline magnet 360 within the recirculation loop 340effectively ensures that the whole flow is within the magnetic field.Additionally, the flow meter effectively ensures that the velocity offlow is decreased sufficiently to prevent erosion of the bound particlesfrom the magnetic surface within the chamber. The shape of therecirculation loop can be configured to enable the magnetic field toattract small particles out of a viscous stream. Moreover, theconfiguration of FIG. 4 permits the metal particles to be readily dumpedwhen the magnet is de-energized.

For some embodiments, the flow chamber is a vertical two-inch thickcavity, which is approximately fourteen inches in width andapproximately thirty-two inches in height. The bottom and the top of theflow chamber are concentric transitions to four inches and three inches,respectively. For such embodiments, the three-inch inlet is at thebottom of the rectangular face opposite the magnet with the flowdirected toward the magnet.

Within the chamber, the flow is upward for some embodiments. For suchembodiments, the flow dynamics naturally direct the densest particles tothe sides. The thin channel forces the whole flow into close proximityto the magnet. Preferably, to withstand the 200 pounds-per-square-inch(psi) pressure in the system, the flow chamber is clamped to the magnetface. To facilitate the release of the particles on de-energizing themagnet, the chamber is constructed, preferably, of stainless steel. Forsome embodiments, the strength of the magnetic field is maximized bymachining the back plate to allow the poles of the magnet to be onlyfractions of an inch from the face which holds the particles.

Stated differently, the pipeline magnet 360 includes an inlet (whichreceives the mixture 355), a fluid outlet (which expels the output 365),a metal outlet (which expels the ferromagnetic material 361), and aselectively activated magnet 362. The inlet, the fluid outlet, and themetal outlet each have a valve that can selectively open and close itsrespective inlet and outlets.

For some embodiments, the selectively activated magnet 362 can be anelectromagnet that activates and deactivates with the supply and removalof power. For other embodiments, the selectively activated magnet 362can be a permanent magnet that is moved toward and away from thepipeline in order to activate and deactivate the magnet by changing itsfringe fields.

In operation, for some embodiments, the opening and closing of the inletand the outlets is timed with the activation and deactivation of themagnet 362 in the following manner. During normal operation, the metaloutlet is closed, while the inlet and the fluid outlet are opened. Fornormal operation, the magnet 362 is activated. Thus, as the mixture 355enters the inlet, the ferromagnetic material 361 is attracted to theactivated magnet 362, while the non-metallic output 365 is expelledthrough the fluid outlet.

During discharge operation, the metal outlet is opened, while the fluidoutlet and the inlet are closed. For the discharge operation, the magnet362 is deactivated. Thus, any ferromagnetic material 361 that waspreviously held by the magnetic force is now released. Since there is nomixture 355 entering, and since the fluid outlet is closed, the releasedferromagnetic material 361 flows out of the metal outlet for disposal orrecycling.

When normal operation resumes, the process repeats itself. Thus, themetals within the recirculation loop are gathered and disposed ofautomatically.

Preferably, the inlet and the outlets have a smaller cross-sectionalflow area than the chamber that is coupled to the magnet 362. As such,the fluid dynamics dictate that the inlet ejects the mixture 355 intothe chamber at a relatively high velocity. The heavier particles, suchas the metals, are propelled toward the magnet due to the momentum ofthe particles as they enter the chamber. The lighter particles, however,are directed to the fluid outlet due to their loss in speed as theyenter the chamber. This is caused by the chamber having a largercross-sectional flow area than the cross-sectional flow area of eitherthe inlet or the fluid outlet.

Such a configuration, as described above with reference to FIG. 4,permits removal of tramp magnetic material with minimal, if any, humanintervention. Also, for various embodiments, there is only a limitedpurge of the flowing material, and the flow is only interrupted brieflyto accomplish that purge.

As shown with reference to FIGS. 1 through 4, multi-stage wasteprocessing systems and processes result in greater waste removal.Additionally, such processes and systems permit recycling of variousmaterials, which would otherwise not be permitted.

Although exemplary embodiments have been shown and described, it will beclear to those of ordinary skill in the art that a number of changes,modifications, or alterations to the disclosure as described may bemade. For example, while two different types of thermal heating (oil andelectric) are shown for the screws in the two chambers, it should beappreciated that both screws can be electrically heated. Also, whilevarious dimensions are provided for clarity and completeness (e.g.,length and diameter of screws, dimensions of chambers, etc.), it shouldbe appreciated that these dimensions can be altered to accommodatevarious needs. Furthermore, while a two-stage heating process isdescribed in great detail above, it should be appreciated thatadditional stages may be added to further process the waste material.All such changes, modifications, and alterations should therefore beseen as within the scope of the disclosure.

1. A waste processing system, comprising: a chamber; an inlet configured to selectively open and close, the inlet further being configured to inject waste material into the chamber when the inlet is open, the waste material being suspended in a fluid medium, the waste material comprising ferromagnetic substances, the waste material further comprising non-ferromagnetic substances; a selectively activated magnet operatively coupled to the chamber, the magnet being configured to activate when the inlet is substantially open, the magnet further being configured to deactivate when the inlet is substantially closed, the magnet being configured to substantially attract the ferromagnetic substances from the waste material when the magnet is activated, the magnet further being configured to release any attracted ferromagnetic substances when the magnet is deactivated; a metal outlet configured to selectively open and close, the metal outlet being configured to open when the magnet is deactivated, the metal outlet further being configured to expel the released ferromagnetic substances from the chamber when the magnet is deactivated; and a fluid outlet configured to selectively open and close, the fluid outlet being configured to open when the magnet is activated, the fluid outlet further being configured to expel waste material remaining after the magnet has substantially attracted the ferromagnetic substances.
 2. The system of claim 1, wherein the selectively activated magnet is operatively coupled to the exterior of the chamber.
 3. The system of claim 1, wherein the selectively activated magnet is an electromagnet, the electromagnet being activated by supplying power to the electromagnet, the electromagnet being deactivated by depriving the electromagnet of power.
 4. The system of claim 1, wherein the selectively activated magnet is a permanent magnet, the permanent magnet being activated by decreasing its proximity to the chamber, the permanent magnet being deactivated by increasing its proximity to the chamber.
 5. The system of claim 1: wherein the chamber has a predefined cross-sectional flow area; wherein the inlet has a cross-sectional flow area that is smaller than the cross-sectional flow area of the chamber; and wherein the fluid outlet has a cross-sectional flow area that is smaller than the cross-sectional flow area of the chamber.
 6. The system of claim 5, the metal outlet has a cross-sectional flow area that is smaller than the cross-sectional flow area of the chamber.
 7. The system of claim 5, further comprising: means for selectively opening and closing the inlet; means for selectively opening and closing the fluid outlet; and means for selectively opening and closing the metal outlet.
 8. The system of claim 5: wherein the inlet has an inlet valve configured to selectively open and close the inlet; wherein the fluid outlet has a fluid outlet valve configured to selectively open and close the fluid outlet; and wherein the metal outlet has a metal outlet valve configured to selectively open and close the metal outlet.
 9. The system of claim 8, wherein the inlet valve, the fluid outlet valve, and the metal outlet valve are operatively coupled to the selectively activated magnet, the selectively activated magnet being configured to control the opening and the closing of the inlet valve, the selectively activated magnet further being configured to control the opening and the closing of the fluid outlet valve, and the selectively activated magnet further being configured to control the opening and the closing of the metal outlet valve.
 10. A method comprising the steps of: injecting waste material into a chamber at a predefined rate, the waste material being suspended in a fluid medium, the waste material having ferromagnetic substances suspended in the fluid medium; activating a magnet when the waste material is being injected into the chamber, the activated magnet substantially attracting the ferromagnetic substances that are suspended in the fluid medium, the attraction of the ferromagnetic substances resulting in a remaining waste material; expelling the remaining waste material from the chamber.
 11. The method of claim 10, further comprising the steps of: stopping the injection of the waste material into the chamber; deactivating the magnet, the deactivating of the magnet resulting in a release of the attracted ferromagnetic substances; and expelling the released ferromagnetic substances from the chamber.
 12. The method of claim I 1, further comprising the steps of: reactivating the magnet; and resuming the injection of the waste material into the chamber. 